Modeling Earth's atmosphere and magnetic field from 41,000 years ago suggests how Homo sapiens' sun-fighting strategy helped sustain them as a species.
Just because Homo sapiens hadn't yet developed the SPF rating system 41,000 years ago didn't mean that they were unaware that solar radiation could prove hazardous. H. sapiens applied some form of sunscreen, shielded themselves from UV rays with clothes, and avoided the ravages of the sun by hiding in caves, according to an article in the journal Science Advances. In fact, those strategies may have helped their populations expand throughout Europe and Asia during a time when Neanderthals, who didn't appear to make these adaptations, were declining. "What some of the differences are between these species, between Neanderthals and anatomically modern humans, that might account for that disappearance has been a major anthropological question for decades," Raven Garvey, a University of Michigan anthropologist and an author of the study, said in a press release. Homo sapiens Sun-Fighting Strategies Researchers found that these sun-fighting strategies roughly coincided with a period when the North Pole moved closer to Europe as the Earth's magnetic field's poles started to move — a process that has happened an estimated 180 times during the Earth's existence. That process weakened the magnetic field, caused auroras to occur throughout most of the globe, and allowed more UV light through the atmosphere. Meanwhile, archaeological evidence shows that, during this time period, H. sapiens started sewing clothing and rubbing ochre, a sun-blocking mineral, on their skin. Living in caves then also provided some protection. "In the study, we combined all of the regions where the magnetic field would not have been connected, allowing cosmic radiation, or any kind of energetic particles from the sun, to seep all the way in to the ground," Agnit Mukhopadhyayan, an author of the paper, and a University of Michigan researcher, said in a press release. "We found that many of those regions actually match pretty closely with early human activity…